Brain Physics Begins To Unravel Mysteries Of Chronic Pain

Electroencephalogram (EEG) readings are abnormal in people with the chronic pain disorder fibromyalgia, reflecting their explosively active neural network.

By Aliyah Kovner

08 Feb 2018, 20:23

A collaborative study by anesthesiologists and physicists shows that the brains of people with the pain disorder fibromyalgia are primed to be overly reactive compared to a normal brain.

The research, now published in Scientific Reports, is one of the first neurological investigations to examine a phenomenon called explosive synchronization (ES) – a state of hyperreactive electrical propagation through a network. The concept had been studied extensively in physics before similar conditions of rapid, widespread signaling were observed in the brains of people with epilepsy and those awakening from anesthesia.

Fibromyalgia (FM) is characterized by systemic pain that's triggered without an actual injury. Strange as it may sound, all pain is simply a creation of the brain. Constantly receiving billions of sensory messages from neurons throughout the body, the brain must interpret the data and decide whether or not the stimulusis a threat. If this ancient self-defense pathway, called nociception, decides the signals reflect danger, it creates the feeling of pain to get the attention of other sections of the brain.

Chronic pain like that of FM develops when the brain begins to sound the pain alarm in response to subtle sensory input that would otherwise be ignored. Neurologists are beginning to unravel how and why this occurs, but like so much about our minds, a good deal remains mysterious.

Given the prominent role of oversensitive nerves in fibromyalgia, the authors hypothesized that the brains of those with the disease would display an ES state. Electroencephalogram (EEG) readings from 10 FM patients were taken at baseline and during light electrical stimulation of pain-related brain areas using an external current-generating device.

The baseline results confirmed that fibromyalgia brains show ES, and those who reported worse pain levels had more dramatic ES responses.

It’s unknown for now, however, whether fibromyalgia develops because a person is born with an ES-prone neural network or if onset of the disease causes alterations to brain structure.

“The jury is still out on this,” Dr Richard Harris told IFLScience. “We don’t have enough prospective brain neuroimaging studies that scan folks' pre-chronic pain to know whether or not the brain outcomes we see in the patients were there all along or if they started after the development of pain. We do know that interventions that work to reduce pain in fibromyalgia also normalize these markers, suggesting that there is a close association."

Our current arsenal of fibromyalgia treatments includes physical therapy, pain medication, and emotional support/therapy, but these interventions don't address the unknown underlying mechanism. Dr Harris hopes that his group's preliminary work could eventually advance the development of personalized therapies that calm each patient's overactive pain response by converting their ES brain state into a stable, behaving network.